View instructions
Safely pulling double and triple trailers requires knowledge and skill. If you want to pull double or triple trailers, you must add the Doubles/Triples (T) endorsement to your Class A CDL. The Idaho doubles triples test consists of 20 questions. To pass, you must correctly answer at least 16 questions (80%). The ID CDL doubles triples test covers the following sections of the Idaho CDL Manual: Driving Safely, Air Brakes (if you plan to operate vehicles equipped with air brakes), Combination Vehicles, Doubles and Triples. Take this ID CDL practice test now to prepare for the actual test! Important: Triple trailers are not legal in Idaho.
1. How does ABS help you?
ABS helps you avoid wheel lock up and maintain control when you brake hard on slippery surfaces.
ABS makes stab braking more effective.
ABS replaces your normal brakes and helps you  to stop faster.
2. _________ rigs are much more likely to roll over in an accident than _________ rigs.
Fully loaded ; empty
Fully loaded ; overloaded
Empty ; fully loaded
3. Which of the following is a common cause of truck fires?
Short circuits due to loose connections.
Under-inflated tires and duals that touch.
All of the above.
4. When transporting cargo, cargo securement must be checked within the first _____ miles of a trip and every _____ miles after.
50; 150
100; 150
50; 250
5. At dawn, dusk, in rain or snow, to make yourself easier to see you should:
use the emergency flashers.
use the high beams.
use the low beams.
6. If the safety relief valve in the air brake system releases air:
this will supply more power to the brakes.
something is wrong.
the valve is fully operational.
7. When a tire fails, you should:
stay off the brake.
brake in a way that will keep your vehicle in a straight line.
push the brake pedal down gradually.
8. Many large vehicles have convex (curved, "spot, "fisheye") mirrors. Convex mirrors:
misrepresent reality by showing a larger area than flat mirrors.
are illegal in most states.
make things look smaller and farther away than they really are.
9. ABS:
improves your visibility at night.
helps you avoid skids caused by over braking.
helps you stop faster.
10. If you unlock the pintle hook with the dolly still under the rear trailer:
your vehicle might roll away.
the dolly tow bar may fly up.
the brakes could be damaged by the combined forces of the springs and the air pressure.
Page 1 of 2
Next page

ID CDL Doubles Test

Number of questions: 20
Correct answers to pass:16
Passing score:80%
Share This Online CDL Test
Rate this CDL Doubles Test
4.9 out of 5
based on 305 votes